Keep quiet about wait (8)
I believe the answer is:
preserve
'keep' is the definition.
(preserving is a kind of keeping)
'quiet about wait' is the wordplay.
'quiet' becomes 'p' (music symbol for 'piano').
'about' becomes 're' (regarding**).
'wait' becomes 'serve' (I've seen this before).
'p'+'re'+'serve'='PRESERVE'
(Other definitions for preserve that I've seen before include "Prevent from rotting" , "Toast option" , "defend" , "Keep from decay in perverse way" , "Keep from decay, corpse or food" .)